I think that was Zeke playing up to David's neurotic weakness, personally. Like that whole thing Bret and Zeke did at the tribal was to rattle David to the point of making him screw up. Shitty? Yes. But no more shitty than the lying, backstabbing, and complete betrayal that seems to be not only celebrated, but encouraged in this game.
Will just showed why everyone didn't take him seriously, because he IS an 18 year old kid who doesn't have the maturity to handle situations. However, I do think Adam playing the idol was the right move in the moment. They had no idea what will was going to do, and I'm not going to let my fate ride on an 18 year old waffling. Ken's move was bad as well, although, I have to wonder if he was thinking that would cause discord in the opposing alliance to the point that they would want to move against Will, and then Ken would rally his side to to the same. His just walking away after stirring the shit made me think so.
I do agree that I love this season, and it's been the most entertaining for me in a long time. I don't have any one player that I hate, and I like watching them play this out. Are bad moves made? Yep, there are. But this idea that people will pull off flawless games in the midst of great personality clashes piled on top of the already existing layer of physical adversity of starvation and sleep deprivation is kind of crazy. Yes, players have dominated, but it was because they won the survivor lottery and were surrounded by idiots or sheep (Boston Rob being the prime example).